Related Stories

True measure Being able to lie about your age may soon be a thing of the past, after a new study shows the human brain develops at a consistent rate across individuals.

The finding could also advance our understanding of autism and ADHD, and be used in a court of law.

The team of US researchers used different magnetic resonance imaging (MRI) techniques to scan the brains of 885 people aged between 3 and 20 years. The images were used to identify more than two hundred structural brain features known to change over time in this age group.

"We have uncovered a 'developmental clock' of sorts within the brain -a biological signature of maturation that captures age differences quite well, regardless of other kinds of differences that exist across individuals," says Dr Timothy Brown of the University of California, San Diego, lead author of the study, which appears in the journal Current Biology.

The researchers were able to assess an individual's age with more than 92 per cent accuracy, beyond what's been possible with any other biological measure.

"The fact that we found a collection of brain measures that so accurately captures a person's chronological age means that brain development, or at least certain anatomical aspects of it, is more tightly controlled than we knew previously," Brown says.

"The regularity in this maturity metric among typically developing children suggests that it might be sensitive to detecting abnormality as well."

Insights in autism and ADHD

Child and adolescent psychiatrist Professor Rhoshel Lenroot from Neuroscience Research Australia says this research, if it can be replicated, offers a unique opportunity to understand the mechanisms underlying disorders such as ADHD and autism.

"One of the big questions that we've had is, are neurodevelopmental disorders to do with the rate of development or are they just wrong development," says Lenroot.

For example, studies of cortical thickness in people with ADHD suggests the cortex develops more slowly but at the same time, a number of people with ADHD continue to experience symptoms in adulthood, even after cortical growth has 'caught up'.

"It would be marvellous to be able to look at that same data set and track this combined phenotype and say, 'does it really look like it was just slow or is there something that is looking different?'," Lenroot says.

The data might one day also be used to argue that someone with the neurodevelopmental features of a minor should not be tried as an adult, Lenroot says.

"I think that the use of neuroimaging in the legal system can get started long before the data really is robust enough to be a good use of it, so I wouldn't be surprised if it started showing up."